Does this Covetous Shen quote have a deeper meaning?
"Except for this part. I've seen this somewhere before."
This is a hint at the fact that some of the models in the dungeons are reused. Blizzard is poking fun at themselves here.
The easiest example case is the underbridge zone in act 3 (random side dungeon sometimes accessible from Rakkis Crossing), you'll often see that exact shape appear in the Keep (somewhere between level 1-3)
It's actually a throwback to Big Trouble In Little China where the actor was in the sewers near the end of the movie.